A family from New Jersey is hoping the kindness of strangers can help lift the spirits of a 4-year-old girl battling a life-threatening brain tumor.

Just a few weeks ago, Lena Tietjen was playing with her twin brother Clark, running around like every other kid on their Vineland block. But then she came down with what they thought was a typical stomach virus.

"We took her to the doctor's office, and they thought she'd get better in a few days," mom Erin Tietjen said. "But she didn't, and the symptoms started getting worse."

After Lena began having difficulty with motor functions on the right side of her body, her panicked parents rushed her to the emergency room. She was transferred to Children's Hospital of Philadelphia, where a scan revealed a mass deep within her brain.

After surgery to drain fluid and five days in the ICU, the results of a biopsy were devastating: Lena was diagnosed with an inoperable malignant tumor and given just months to live without treatment.

"It's the worst moment of your life," dad Matt Tietjen said. "She's so innocent. Your main job as a parent is to keep your child safe, and this was completely out of our control."

Lena has been in and out of the hospital ever since, learning to complete daily tasks with her left hand, while doctors determine the best approach to what will be the fight of her life. The family has adopted the nickname "Lena the Lion" to reflect her tenacious spirit.

With radiation and chemotherapy set to begin in early December, doctors are hopeful she will survive one year.

"We will fight that prognosis with everything we have," Erin said. "We will go anywhere, try anything. Whatever we can do to give her a chance."

A relative has set up a GoFundMe page to help cover the costs of treatment, travel and other related expenses. In the meantime, as the holiday season approaches, they are hoping family, friends and anyone willing to participate can help their strong little girl stay positive with what they have dubbed "Lena's Library."

"She loves books so much and loves to be read to," said Erin, who works as an English teacher. "We just want her to be happy and loved, and know that people care about her."

Anyone who wishes to send Lena a new or gently used children's book can mail it to:

Lena's LibraryGeneral Delivery1539 Almond RoadVineland, NJ 08360

The family knows the road ahead will be difficult, but they also realize the importance of staying optimistic while hoping for a miracle.

"I had a moment in the hospital where I broke down and ducked into the bathroom," Matt said. "Erin came in and said, 'You can't do this. No story about beating the odds ever started out with good odds.' So we have to be strong for her, no matter how much it is tearing us up inside."

Note: Please CLICK HERE if you are attempting to purchase a book through Amazon. A wishlist had to be created to keep the Tietjens' address private, as Amazon does not recognize the Post Office as a valid mailing address.